Olefin trimerisation using a catalyst comprising a source of chromium,molybdenum or tungsten and a ligand containing at least one phosphorous, arsenic or antimony atom bound to at least one (hetero)hydrocarbyl group

ABSTRACT

A process for the trimerisation of olefins is disclosed, comprising contacting a monomeric olefin or mixture of olefins under trimerisation conditions with a catalyst which comprises (a) a source of chromium, molybdenum or tungsten (b) a ligand containing at least one phosphorus, arsenic or antimony atom bound to at least one hydrocarbyl or heterohydrocarbyl group having a polar substituent, but excluding the case where all such polar substituents are phosphane, arsane or stibana groups; and optionally (c) an activator.

[0001] This invention relates to the trimerisation of olefins, such asthe preparation of 1-hexene by the trimerisation of ethylene.

[0002] U.S. Pat. No. 5,198,563 and related patents by Phillips describechromium-containing catalysts containing monodentate amide ligandsuseful for trimerising olefins.

[0003] U.S. Pat. No. 5,968,866 discloses an ethyleneoligomerisation/trimerisation process which uses a catalyst comprising achromium complex which contains a coordinating asymmetric tridentatephosphane, arsane or stibane ligand (referred to therein as phosphine,arsine or stibine, and representing a phosphorus, arsenic or antimonyatom attached to three hydrocarbyl groups) and an aluminoxane to producealpha-olefins which are enriched in 1-hexene. There is no suggestionthat it is possible to replace any of the phosphane, arsane or stibanegroups: indeed, it is impossible to predict what the effect of such areplacement would be.

[0004] We have now discovered further ligands which when used inconjunction with a source of a Group 3 to 10 transition metal aresignificantly more active as trimerisation catalysts than thosecurrently known, and also show other advantageous properties. Theinvention also encompasses within its scope novel catalysts comprisingsuch ligands in conjunction with a source of chromium, molybdenum ortungsten.

[0005] Accordingly in a first aspect, the present invention provides acatalyst for the trimerisation of olefins, comprising

[0006] (a) a source of chromium, molybdenum or tungsten;

[0007] (b) a ligand containing at least one phosphorus, arsenic orantimony atom bound to at least one hydrocarbyl or heterohydrocarbylgroup having a polar substituent, but excluding the case where all suchpolar substituents are phosphane, arsane or stibane groups; andoptionally

[0008] (c) an activator.

[0009] In this specification the term “trimerisation” means catalyticreaction of a single olefinic monomer or a mixture of olefinic monomersto give products enriched in those constituents derived from thereaction(s) of three olefinic monomers, as distinct from polymerisationor oligomerisation, which typically give olefinic product distributionsgoverned by either a geometric series equation or following a Poissonpattern of distribution. “Trimerisation” includes the case where all themonomer units in the trimerisation product are identical, where thetrimerization product is made from two different olefins (i.e. twoequivalents of one monomer react with one equivalent of a secondmonomer), and also where three different monomer units react to yieldthe product. A reaction involving more than one monomer is oftenreferred to as cotrimerisation.

[0010] It will be appreciated that the above catalyst may either beformed prior to use in a trimerisation reaction, or it may be formed insitu by adding the individual components thereof to the reactionmixture.

[0011] In a further aspect, the invention provides a process for thetrimerisation of olefins, comprising contacting a monomeric olefin ormixture of olefins under trimerisation conditions with a catalyst whichcomprises

[0012] (a) a source of a Group 3 to 10 transition metal;

[0013] (b) a ligand containing at least one phosphorus, arsenic orantimony atom bound to at least one hydrocarbyl or heterohydrocarbylgroup having a polar substituent, but excluding the case where all suchpolar substituents are phosphane, arsane or stibane groups; andoptionally

[0014] (c) an activator.

[0015] We have also found that the catalysts used in the above processhave certain novel features. For example, such catalysts when supportedlose less of their activity compared with the equivalent unsupportedcatalyst than known catalysts. A further aspect of the inventiontherefore is a supported catalyst having a productivity per mole ofcatalyst of at least 50%, preferably at least 70% of its productivitywhen unsupported, which catalyst preferably comprises

[0016] (a) a source of a Group 3 to 10 transition metal;

[0017] (b) a ligand containing at least one phosphorus, arsenic orantimony atom bound to at least one hydrocarbyl or heterohydrocarbylgroup having a polar substituent, but excluding the case where all suchpolar substituents are phosphane, arsane or stibane groups; andoptionally

[0018] (c) an activator.

[0019] Additionally, we have found that such catalysts have unusuallyhigh productivity, and maintain that productivity particularly well.Accordingly one further aspect of the invention comprises a catalyst forthe trimerisation of olefins, which has a productivity of at least 30000g product per mmol catalyst per hour at a temperature of 110° C. or lessand an ethylene partial pressure of 21 bar or less. Another aspect ofthe invention is a catalyst for the trimerisation of olefins, whereinthe catalyst productivity decays at a rate of less than 10% per hour.

[0020] In one embodiment of the process of the invention, the catalystutilised in the present invention additionally comprises a furthercatalyst (d) suitable for the polymerisation, oligomerisation or otherchemical transformations of olefins. In processes wherein such anadditional catalyst is present, the trimerisation products areincorporated into a higher polymer or other chemical product.

[0021] The catalysts used in the trimerisation process of the inventionshow exceptionally high productivity and selectivity to 1-hexene withinthe product fraction containing 6 carbon atoms. The high productivity ofthe catalysts results in greater process efficiency and/or lowerintrinsic levels of catalyst residues. The high selectivity of thecatalysts results in a greater ease of product purification (resultingeither in less costly product purification or purer products). Theseadvantages would be expected to apply both to processes whereincatalysts according to the invention comprise the sole catalyticcomponent and also to integrated processes, for example in theproduction of branched polyolefins, where more than one transition metalcatalyst is employed.

[0022] As regards the source of Group 3 to 10 transition metal (a), thiscan include simple inorganic and organic salts, for example, halides,acetylacetonates, carboxylates, oxides, nitrates, sulfates and the like,as well as co-ordination and organometallic complexes, for example,chromium trichloride tetrahydrofuran complex,(benzene)tricarbonylchromium, chromium hexacarbonyl, molybdenumhexacarbonyl and the like. Preferably component (a) is a source ofchromium, molybdenum or tungsten; particularly preferred is chromium.

[0023] The ligand of component (b) preferably has the formula

[0024] (R¹)(R²)X-Y-X(R³)(R⁴), wherein

[0025] X is phosphorus, arsenic or antimony;

[0026] Y is a linking group;

[0027] and R¹, R², R³ and R⁴ are each independently hydrocarbyl,substituted hydrocarbyl, heterohydrocarbyl or substitutedbeterohydrocarbyl groups, at least one of which has a polar substituentwhich is not a phosphane, arsane or stibane group.

[0028] An alternative preferred structure for the ligand of component(b) is X(R¹)(R²)(³) wherein X and R¹, R² and R³ are as defined above,with at least one of R¹, R² and R³ having a polar substituent which isnot a phosphane, arsane or stibane group.

[0029] X is preferably phosphorus. As regards R¹, R², R³ and R⁴,examples of suitable hydrocarbyl groups are methyl, ethyl, ethylenyl,propyl, butyl, cyclohexyl, benzyl, phenyl, tolyl, xylyl, mesityl,biphenyl, naphthyl, anthracenyl and the like. Examples of suitablebeterohydrocarbyl groups are methoxy, ethoxy, phenoxy (i.e. —OC₆H₅),tolyloxy (i.e. —OC₆H₄(CH₃)), xylyloxy, mesityloxy, dimethylamino,diethylamino, methylethylamino, thiomethyl, thiophenyl, trimethylsilyl,dimethylhydrazyl and the like.

[0030] Preferably those of R¹ to R⁴ having polar substituents aresubstituted aryl groups with at least one polar substituent. Suitablesubstituted aryl groups include substituted phenyl, substituted naphthyland substituted anthracenyl groups. Substituted phenyl is preferred.Polar substituents include methoxy, ethoxy, isopropoxy, C₃-C₂₀ alkoxy,phenoxy, pentafluorophenoxy, trimethylsiloxy, dimethylamino,methylsulphanyl, tosyl, methoxymethyl, methylthiomethyl, 1,3-oxazolyl,methoxymethoxy, hydroxyl, amino, sulphate, nitro and the like. Othersuitable polar substituents include phosphanes, arsanes and stibanes asdescribed in U.S. Pat. No. 5,968,866 (but subject to the above-mentionedproviso that at least one of R¹ to R⁴ has a polar substituent which isnot one of these). Ortho-substituted phenyl groups are most preferred;the ortho substituent is preferably alkoxy, more preferably methoxy ormethoxymethoxy. The phenyl groups may additionally be substituted in themeta and para or other ortho positions by groups such as hydrocarbyl,heterohydrocarbyl, substituted hydrocarbyl, halide and the like; but itis preferred that they are unsubstituted in these other positions.

[0031] Preferably any of R¹ to R⁴ which do not have polar substituentsare independently optionally substituted phenyl groups; substituents maybe hydrocarbyl, heterohydrocarbyl, substituted hydrocarbyl, substitutedheterohydrocarbyl, halide and the like. However it is most preferredthat all of R¹ to R⁴ have polar substituents as defined above, which arenot phosphane, arsane or stibane groups. It is also most preferred thatR¹ to R⁴ are the same.

[0032] Y may be any bridging group, for example hydrocarbyl, substitutedhydrocarbyl, heterohydrocarbyl, substituted hydrocarbyl or substitutedheterohydrocarbyl bridging groups, or inorganic bridging groupsincluding single atom links such as —O—. Y may optionally contain anadditional potential donor site. Examples of Y include methylene,1,2-ethane, 0.1,2-phenylene, 1,3-propane, 1,2-catechol,1,2-dimethylhydrazine, —N(R⁵)—where R⁵ is hydrogen, hydrocarbyl, orsubstituted hydrocarbyl, and the like. Preferably Y is —N(⁵)—;preferably R⁵ is hydrogen, C₁-C₆ alkyl or phenyl, more preferablymethyl.

[0033] Any of the groups R¹-R⁴ may independently be linked to one ormore of each other or to the bridging group Y, to form a cyclicstructure together with X or X and Y.

[0034] The ligands can be prepared using procedures known to one skilledin the art and disclosed in published literature. Examples of preferredcompounds are:

[0035] (2-methoxyphenyl)(phenyl)PN(Me)P(phenyl)₂

[0036] (2-methoxyphenyl)₂PN(Me)P(phenyl)₂

[0037] (2-methoxyphenyl)(phenyl)PN(Me)P(2-methoxyphenyl)(phenyl)

[0038] (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂

[0039] (2-ethoxyphenyl)₂PN(Me)P(2-ethoxyphenyl)₂

[0040] (2-isopropoxyphenyl)₂PN(Me)P(2-isopropoxyphenyl)₂

[0041] (2-hydroxyphenyl)₂PN(Me)P(2-hydroxyphenyl)₂

[0042] (2-nitrophenyl)₂PN(Me)P(2-nitrophenyl)₂

[0043] (2,3-dimethoxyphenyl)₂PN(Me)P(2,3-dimethoxyphenyl)₂

[0044] (2,4-dimethoxyphenyl)₂PN(Me)P(2,4-dimethoxyphenyl)₂

[0045] (2,6-dimethoxyphenyl)2PN(Me)P(2,6-dimethoxyphenyl)₂

[0046] (2,4,6-trimethoxyphenyl)2PN(Me)P(2,4,6-trimethoxyphenyl)2

[0047] (2-dimethoxyphenyl)(2-methylphenyl)PN(Me)P(2-methylphenyl)₂

[0048] [2-(dimethylamino)phenyl]2PN(Me)P[2-(dimethylamino)phenyl]2

[0049] (2-methoxymethoxyphenyl)₂PN(Me)P(2-methoxymethoxyphenyl)₂

[0050] (2-methoxyphenyl)₂PN(Ethyl)P(2-methoxyphenyl)₂

[0051] (2-methoxyphenyl)₂PN(Phenyl)P(2-methoxyphenyl)₂

[0052] (2-methoxyphenyl)₂PN(Me)N(Me)P(2-methoxyphenyl)₂

[0053] (2-methoxyphenyl)₂PCH₂P(2-methoxyphenyl)₂

[0054] (2-methoxyphenyl)₂PCH₂CH₂P(2-methoxyphenyl)₂

[0055] tri(2-methoxymethoxyphenyl)phosphane i.e.

[0056] tri(2-methoxyphenyl) phosphane.

[0057] Components (a) and (b) may be present in any ratio, preferablybetween 10000:1 and 1:10000; more preferred is a ratio between 100:1 and1:100, and especially preferred is a ratio of 10:1 to 1:10, particularly3:1 to 1:3. Generally the amounts of (a) and (b) are approximatelyequal, ie a ratio of between 1.5:1 and 1:1.5.

[0058] The activator compound (c) may in principle of be any compoundthat generates an active catalyst with components a) and b). Mixtures ofactivators may also be used. Suitable compounds include organoaluminiumcompounds, organoboron compounds and inorganic acids and salts, such astetrafluoroboric acid etherate, silver tetrafluoroborate, sodiumhexafluoroantimonate and the like. Suitable organoaluminium compoundsinclude compounds of the formula AlR₃, where each R is independentlyC₁-C₁₂ alkyl, oxygen or halide, and compounds such as LiAlH₄ and thelike. Examples include trimethylaluminium (TMA), triethylaluminium(TEA), tri-isobutylaluminium (TIBA), tri-n-octylaluminium,methylaluminium dichloride, ethylaluminium dichloride, dimethylaluminiumchloride, diethylaluminium chloride, ethylaluminiumsesquichloride,methylaluminiumsesquichloride, and alumoxanes. Alumoxanes are well knownin the art as typically oligomeric compounds which can be prepared bythe controlled addition of water to an alkylaluminium compound, forexample trimethylaluminium. Such compounds can be linear, cyclic, cagesor mixtures thereof. Commercially available alumoxanes are generallybelieved to be mixtures of linear and cyclic compounds. The cyclicalumoxanes can be represented by the formula [R⁶AlO]_(s) and the linearalumoxanes by the formula R⁷(R⁸AlO)_(s) wherein s is a number from about2 to 50, and wherein R⁶, R⁷, and R⁸ represent hydrocarbyl groups,preferably C₁ to C₆ alkyl groups, for example methyl, ethyl or butylgroups. Alkylalumoxanes such as methylalumoxane (MAO) are preferred.

[0059] Mixtures of alkylalumoxanes and trialkylaluminium compounds areparticularly preferred, such as MAO with TMA or TIBA. In this context itshould be noted that the term “alkylalumoxane” as used in thisspecification includes alkylalumoxanes available commercially which maycontain a proportion, typically about 10 wt %, but optionally up to 50wt %, of the corresponding trialkylaluminium; for instance, commercialMAO usually contains approximately 10 wt % trimethylaluminium (TMA),whilst commercial MMAO contains both TMA and TIBA. Quantities ofalkylalumoxane quoted herein include such trialkylaluminium impurities,and accordingly quantities of trialkylaluminium compounds quoted hereinare considered to comprise compounds of the formula AlR₃ additional toany AlR₃ compound incorporated within the alkylalumoxane when present.

[0060] Examples of suitable organoboron compounds are boroxines, NaBH₄,trimethylboron, triethylboron,dimethylphenylammoniumtetra(phenyl)borate, trityltetra(phenyl)borate,triphenylboron, dimethylphenylammonium tetra(pentafluorophenyl)borate,sodium tetrakis[(bis-3,5-trifluoromethyl)phenyl]borate,H⁺(OEt₂)₂[(bis-3,5-trifluoromethyl)phenyl]borate,trityltetra(pentafluorophenyl)borate and tris(pentafluorophenyl) boron.

[0061] Activator compound (c) may also be or contain a compound thatacts as a reducing or oxidising agent, such as sodium or zinc metal andthe like, or oxygen and the like.

[0062] In the preparation of the catalysts utilised in the presentinvention, the quantity of activating compound to be employed is easilydetermined by simple testing, for example, by the preparation of smalltest samples which can be used to trimerise small quantities of themonomer(s) and thus to determine the activity of the produced catalyst.It is generally found that the quantity employed is sufficient toprovide 0.1 to 20,000 atoms, preferably 1 to 2000 atoms of aluminium orboron per atom of chromium. In some cases, for particular combinationsof component a) and b), an activating compound c) may not be required.

[0063] Components (a)-(c) of the catalyst system utilised in the presentinvention maybe added together simultaneously or sequentially, in anyorder, and in the presence or absence of monomer in any suitablesolvent, so as to give an active catalyst. For example, components (a),(b) and (c) and monomer may be contacted together simultaneously, orcomponents (a), (b) and (c) may be added together simultaneously orsequentially in any order and then contacted with monomer, or componentsa) and b) may be added together to form an isolable metal-ligand complexand then added to component c) and contacted with monomer, or components(a), (b) and (c) may be added together to form an isolable metal-ligandcomplex and then contacted with monomer. Suitable solvents forcontacting the components of the catalyst or catalyst system include,but are not limited to, hydrocarbon solvents such as heptane, toluene,1-hexene and the like, and polar solvents such as diethyl ether,tetrahydrofuran, acetonitrile, dichloromethane, chloroform,chlorobenzene, methanol, acetone and the like.

[0064] The catalyst components (a), (b) and (c) utilised in the presentinvention can be unsupported or supported on a support material, forexample, silica, alumina, MgCl₂ or zirconia, or on a polymer, forexample polyethylene, polypropylene, polystyrene, or poly(aminostyrene).It is an advantage of the present invention that very littleproductivity (mass of product per mol of catalyst per hour) is lost whenthe catalyst is supported. If desired the catalysts can be formed insitu in the presence of the support material, or the support materialcan be pre-impregnated or premixed, simultaneously or sequentially, withone or more of the catalyst components. The quantity of support materialemployed can vary widely, for example from 100,000 to 1 grams per gramof metal present in the transition metal compound. In some cases, thesupport may material can also act as or as a component of the activatorcompound (c). Examples include supports containing alumoxane moietiesand/or hydrocarbyl boryl moieties (see, for example, Hlatky, G. G. Chem.Rev. 2000, 100, 1347.) One embodiment of the present inventionencompasses the use of components (a) (b) and optionally (c) inconjunction with one or more types of olefin polymerisation catalyst orcatalyst system (d) to trimerise olefins and subsequently incorporate aportion of the trimerisation product(s) into a higher polymer.

[0065] Component (d) may be one or more suitable polymerisationcatalyst(s) or catalyst system(s), examples of which include, but arenot limited to, conventional Ziegler-Natta catalysts, metallocenecatalysts, monocyclopentadienyl or “constrained geometry” catalysts,beat activated supported chromium oxide catalysts (eg. “Phillips”-typecatalysts), late transition metal polymerisation catalysts (eg. diimine,diphosphine and salicylaldimine nickel/palladium catalysts, iron andcobalt pyridyldiimine catalysts and the like) and other so-called“single site catalysts” (SSC's).

[0066] Ziegler-Natta catalysts, in general, consist of two maincomponents. One component is an alkyl or hydride of a Group I to IIImetal, most commonly Al(Et)₃ or Al(iBu)₃ or Al(Et)₂Cl but alsoencompassing Grignard reagents, n-butyllithium, or dialkylzinccompounds. The second component is a salt of a Group IV to VIIItransition metal, most commonly halides of titanium or vanadium such asTiCl₄, TiCl₃, VCl₄, or VOCl₃. The catalyst components when mixed,usually in a hydrocarbon solvent, may form a homogeneous orheterogeneous product. Such catalysts may be impregnated on a support,if desired, by means known to those skilled in the art and so used inany of the major processes known for co-ordination catalysis ofpolyolefins such as solution, slurry, and gas-phase. In addition to thetwo major components described above, amounts of other compounds(typically electron donors) may be added to further modify thepolymerization behaviour or activity of the catalyst.

[0067] Metallocene catalysts, in general, consist of transistion metalcomplexes, most commonly based on Group IV metals, ligated withcyclopentadienyl (Cp)-type groups. A wide range of structures of thistype of catalysts is known, including those with substituted, linkedand/or heteroatom-containing Cp groups, Cp groups fused to other ringsystems and the like. Additional activators, such as boranes oralumoxane, are often used and the catalysts may be supported, ifdesired.

[0068] Monocyclopentadienyl or “constrained geometry” catalysts, ingeneral, consist of a transition metal complexes, most commonly based onGroup IV metals, ligated with one cyclopentadienyl(Cp)-type group, oftenlinked to additional donor group. A wide range of structures of thistype of catalyst is known, including those with substituted, linkedand/or heteroatom-containing Cp groups, Cp groups fused to other ringsystems and a range of linked and non-linked additional donor groupssuch as amides, amines and alkoxides. Additional activators, such asboranes or alumoxane, are often used and the catalysts may be supported,if desired.

[0069] A typical heat activated chromium oxide (Phillips) type catalystemploys a combination of a support material to which has first beenadded a chromium-containing material wherein at least part of thechromium is in the hexavalent state by heating in the presence ofmolecular oxygen. The support is generally composed of about 80 to 100wt. % silica, the remainder, if any, being selected from the groupconsisting of refractory metal oxides, such as aluminium, boria,magnesia, thoria, zirconia, titania and mixtures of two or more of theserefractory metal oxides. Supports can also comprise alumina, aluminiumphosphate, boron phosphate and mixtures thereof with each other or withsilica. The chromium compound is typically added to the support as achromium (m) compound such as the acetate or acetylacetonate in order toavoid the toxicity of chromium (VI). The raw catalyst is then calcinedin air at a temperature between 250 and 1000° C. for a period of from afew seconds to several hours. This converts at least part of thechromium to the hexavalent state. Reduction of the Cr (VI) to its activeform normally occurs in the polymerization reaction, but can be done atthe end of the calcination cycle with CO at about 350° C. Additionalcompounds, such as fluorine, aluminium and/or titanium may be added tothe raw Phillips catalyst to modify it. Late transition metal and singlesite catalysts cover a wide range of catalyst structures based on metalsacross the transition series (see, for example, Britovsek, G. J. P etal. Angew. Chem. Int. Ed. Engl. 1999, 38, 429. and Ittel, S. D. et al.Chem. Rev. 2000, 100, 1169.

[0070] Component (d) may also comprise one or more polymerisationcatalysts or catalyst systems together with one or more additionaloligomerisation catalysts or catalyst systems. Suitable oligomerisationcatalysts include, but are not limited to, those that dimerise (forexample, nickel phosphine dimerisation catalysts) or trimerise olefinsor otherwise oligomerise olefins to, for example, a distribution of1-olefins governed by a geometric series equation (for example, iron andcobalt pyridyldiimine oligomerisation catalysts).

[0071] Component (d) may independently be supported or unsupported.Where components (a) and (b) and optionally (c) are supported, (d) maybe co-supported sequentially in any order or simultaneously on the samesupport or may be on a separate support. For some combinations, thecomponents (a)-(c) may be part or all of component (d). For example, ifcomponent (d) is a heat activated chromium oxide catalyst then this maybe (a), a chromium source and if component (d) contains an alumoxaneactivator then this may also be the optional activator (c). Thecomponents (a), (b), (c) and (d) may be in any molar ratio. In thecontext of an integrated process the ratio of (a) to (d) is seen asparticularly important. The ratio of (a) to (d) is preferably from10000:1 to 1:10000 and more preferably from 100:1 to 1:100. The preciseratio required depends on the relative reactivity of the components andalso on the desired properties of the product or catalyst systems.

[0072] Suitable olefinic monomers, or combinations thereof for use inthe trimerisation process of the present invention are hydrocarbonolefins, for example, ethylene, C₂₋₂₀ α-olefins, internal olefins,vinylidene olefins, cyclic olefins and dienes, propylene, 1-butene,1-pentene, 1-hexene, 4-methylpentene-1, 1-heptene, 1-octene, 1-nonene,1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene,1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene,1-eicosene, styrene, 2-butene, 2-ethyl-1-hexene, cyclohexene, norbomene,butadiene and 1,5-bexadiene. Olefins with a polar functionality, such asmethyl (meth)acrylate, vinyl acetate, αω-undecenol and the like, mayalso be used. The preferred monomer is ethylene. Mixtures of thesemonomer may also be used, for example a 1-butene unit and two ethyleneunits may be co-trimerised to form C8 olefins, or 1-hexene and ethyleneco-trimerised to C10 olefins, or 1-dodecene and ethylene co-trimerisedto C16 olefins. Combinations of these co-trimerisation reactions may beperformed simultaneously, especially when one or more of the monomersare produced in-situ (e.g. a mixture of ethylene and butene can be usedto form mixtures containing predominantly hexenes, octenes, anddecenes.) Techniques for varying the distribution of products from thesereactions include controlling process conditions (e.g. concentration,reaction temperature, pressure, residence time) and properly selectingthe design of the process and are well known to those skilled in theart. These monomers or combinations thereof are also suitable in thepresence of component (d).

[0073] Olefinic monomers or mixtures of olefinic monomers fortrimerisation may be substantially pure or may contain olefinicimpurities. One embodiment of the process of the invention comprises thetrimerisation of olefin-containing waste streams from other chemicalprocesses or other stages of the same process.

[0074] When operating under solution or slurry phase conditions, anydiluent or solvent that is an olefin, a mixture of olefins, or issubstantially inert under trimerisation conditions may be employed.Mixtures of inert diluents, with or without one or more olefins, alsocould be employed. The preferred diluents or solvents are aliphatic andaromatic hydrocarbons and halogenated hydrocarbons such as, for example,isobutane, pentane, toluene, xylene, ethylbenzene, cumene, mesitylene,beptane, cyclohexane, methylcyclohexane, 1-hexene, 1-octene,chlorobenzene, dichlorobenzene, and the like, and mixtures such asisopar.

[0075] The trimerisation conditions can be, for example, solution phase,slurry phase, gas phase or bulk phase, with temperatures ranging from−100° C. to +300° C., preferably from 0° C. to +300° C. and morepreferably from 35° C. to 200° C., and at pressures of atmospheric andabove, preferably from atmospheric to 800 barg and more preferably from1 barg to 100 barg. If desired, the process can be operated attemperatures above 120° C., and optionally also at pressures below 30barg. The high initial rate and low rate of deactivation of thiscatalyst system enables lower pressures to be employed than would havebeen economically feasible with prior art catalyst systems.

[0076] Irrespective of the trimerisation technique employed,trimerisation is typically carried out under conditions thatsubstantially exclude oxygen, water, and other materials that act ascatalyst poisons. Also, trimerisation can be carried out in the presenceof additives to control selectivity, enhance activity and reduce theamount of polymer formed in trimerisation processes. Suitable additivesinclude, but are not limited to, hydrogen or a halide source such asGeCl₄. Exemplary halides include, but are not limited to fluoride,chloride, bromide, and/or iodide.

[0077] There exist a number of options for the trimerisation reactorincluding batch, semi-batch, and continuous operation. The trimerisationand co-trimerisation reactions of the present invention can be performedunder a range of process conditions that are readily apparent to thoseskilled in the art: as a homogeneous liquid phase reaction in thepresence or absence of an inert hydrocarbon diluent such as toluene orheptanes; as a two-phase liquid/liquid reaction; as a slurry processwhere the catalyst is in a form that displays little or no solubility;as a bulk process in which essentially neat reactant and/or productolefins serve as the dominant medium; as a gas-phase process in which atleast a portion of the reactant or product olefin(s) are transported toor from a supported form of the catalyst via the gaseous state.Evaporative cooling from one or more monomers or inert volatile liquidsis but one method that can be employed to effect the removal of heatfrom the reaction. The trimerisation reactions may be performed in theknown types of gas-phase reactors, such as circulating bed, verticallyor horizontally stirred-bed, fixed-bed, or fluidised-bed reactors,liquid-phase reactors, such as plug-flow, continuously stirred tank, orloop reactors, or combinations thereof. A wide range of methods foreffecting product, reactant, and catalyst separation and/or purificationare known to those skilled in the art and may be employed: distillation,filtration, liquid-liquid separation, slurry settling, extraction, etc.One or more of these methods may be performed separately from thetrimerisation reaction or it may be advantageous to integrate at leastsome with a trimerisation reaction; a non-limiting example of this wouldbe a process employing catalytic (or reactive) distillation. Alsoadvantageous may be a process which includes more than one reactor, acatalyst kill system between reactors or after the final reactor, or anintegrated reactor/separator/purifier. While all catalyst components,reactants, inerts, and products could be employed in the presentinvention on a once-through basis, it is often economically advantageousto recycle one or more of these materials; in the case of the catalystsystem, this might require reconstituting one or more of the catalystscomponents to achieve the active catalyst system. It is within the scopeof this invention that a trimerisation product might also serve as areactant (e.g. 1-hexene, produced via the trimerization of ethylene,might be converted to decene products via a subsequent co-trimerizationreaction with ethylene.)

[0078] A number of process options can be envisaged when using thecatalysts of the present invention in an integrated process thatincludes a subsequent chemical transformation, i.e. with component (d)present. These options include “in series” processes in which thetrimerisation and subsequent reaction are performed in separate, linkedreactors, optionally with recycling of products/reagents between thereactors, and “in situ” processes in which a both reaction steps arecarried out in the same reactor. Chemical transformations involvingolefins are well known to those skilled in the art:

[0079] non-limiting examples of the chemical reactions that might beeffected by use of a component (d) include polymerisation andco-polymerisation, oligomerisation, hydrogenation, hydroformylation,oxidation, hydration, sulfonation, epoxidation, isomerisation,amination, cyclisation, and alkylation. A typical reactor residence timein the polymerisation reactor is less than 4 hours, preferably less than3 hours.

[0080] In the case of an “in series” process various purification,analysis and control steps for the oligomeric product could potentiallybe incorporated between the trimerization and subsequent reactionstages. Recycling between reactors configured in series is alsopossible. An example of such a process would be the trimerisation ofethylene in a single reactor with a catalyst comprising components (a),(b) and optionally (c) followed by polymerisation of the trimerisationproduct with ethylene in a separate, linked reactor to give branchedpolyethylene. Another example would be co-trimerisation of ethylene and1-butene and subsequent polymerisation of the trimerisation product togive poly(octene). Another example would be the trimerisation of anethylene-containing waste stream from a polyethylene process, followedby introduction of the product 1-hexene back into the polyethyleneprocess as a co-monomer for the production of branched polyethylene.

[0081] An example of an “in situ” process is the production of branchedpolyethylene catalysed by components (a), (b), (d) and optionally (c),added in any order such that the active catalytic species derived fromcomponents (a), (b) and optionally (c) is/are at some point present in areactor with component (d)

[0082] Both the “in series and “in situ” approaches can be adaptions ofcurrent polymerisation technology for the process stages includingcomponent (d). All major olefin existing polymerisation processes,including multiple reactor processes, are considered adaptable to thisapproach. One adaption is the incorporation of a trimerisation catalystbed into a recycle loop of a gas phase polymerisation process, thiscould be as a side or recycle stream within the main fluidisationrecycle loop and or within the degassing recovery and recycle system.

[0083] Polymerisation conditions when component (d) is present can be,for example, solution phase, slurry phase, gas phase or bulk phase, withtemperatures ranging from −100° C. to +300° C., and at pressures ofatmospheric and above, particularly from 1.40 to 41 bar. Reactionconditions, will typically have a significant impact upon the properties(e.g. density, melt index, yield) of the polymer being made and it islikely that the polymer requirements will dictate many of the reactionvariables. Reaction temperature, particularly in processes where it isimportant to operate below the sintering temperature of the polymer,will typically, and preferably, be primarily selected to optimise thepolymerisation reaction conditions. The high productivity, and kineticprofile characteristics, of this new trimerisation catalyst makes the‘in-situ’ production of the comonomer, preferably hexene-1, duringpolymer, preferably polyethylene, production far more commerciallyattractive than prior art catalysts systems. This is true even at thetypical reaction temperatures and pressures for the production ofpolyethylenes with high comonomer contents such as LLDPE, VLDPE andULDPE (preferably between 50° C. and 100° C., depending upon the densityof the polymer) and even when used in 5 slurry and gas phasepolymerisation processes (preferably total gas phase pressures between15 and 30 bar and ethylene pressures between 10 and 70 percent of thegas phase). If desired, the catalyst can be used to polymerise ethyleneunder high pressure/high temperature process conditions wherein thepolymeric material forms as a melt in supercritical ethylene. Preferablythe polymerisation is conducted under gas phase fluidized bed or stirredbed conditions. Also, polymerisation or copolymerisation can be carriedout in the presence of additives to control polymer or copolymermolecular weights. The use of hydrogen gas as a means of controlling theaverage molecular weight of the polymer or copolymer applies generallyto the polymerization process of the present invention.

[0084] Slurry phase polymerisation conditions or gas phasepolymerisation conditions are particularly useful for the production ofhigh or low density grades of polyethylene, and polypropylene. In theseprocesses the polymerisation conditions can be batch, continuous orsemi-continuous. Furthermore, one or more reactors may be used, e.g.from two to five reactors in series. Different reaction conditions, suchas different temperatures or hydrogen concentrations may be employed inthe different reactors. In cascade operation the trimerisation catalystmay be added to any or all of the polymerisation reactors concerned. Ifadded to the first reactor and carried through to subsequent reactors,the trimerisation catalyst may, or may not, be supplemented insubsequent reactors with fresh trimerisation or polymerisation catalyst,it may be deactivated in subsequent reactors through addition ofreversible or irreversible poisons that partially or fully kill thetrimerisation catalyst or though addition of additional polymerisationcatalysts or modifiers that deactivate the trimerisation catalyst.

[0085] In the slurry phase process and the gas phase process, thecatalyst is generally supported and metered and transfered into thepolymerization zone in the form of a particulate solid either as a drypowder (e.g. with an inert gas, ethylene or an olefin) or as a slurry.In addition, an optional activator can be fed to the polymerisationzone, for example as a solution, separately from or together with thesolid catalyst. Components (a)-(d) can be added to any part of thepolymerisation reactor either on the same support particle or as aphysical mixture on different support particles, or may be addedseparately to the same or different parts of the reactor sequentially inany order or simultaneously. Alternatively, (a)-(d) may be unsupportedand independently added to any part of the polymerisation reactorsimultaneously or sequentially together or separately. The ratio of theprimary monomer to the other (co)monomers has a significant impact onthe properties of the polymer formed (eg density) and it is usuallydesirable to be tightly controlled. This ratio may be primarilycontrolled by altering the concentration or partial pressure of eitherthe primary monomer and/or the comonomer(s). Typically the primarymonomer concentration will be controlled independently of the ratio tocomonomers (for other reasons such as activity) and the primary monomerto comonomer ratio(s) may be controlled by varying the rate ofintroduction of trimerisation catalyst or by altering reactionconditions which preferentially impact the trimerisation reaction overthe polymerisation reaction or which impacts upon the distribution ofcomonomers actually formed (eg by using reversible poisons/activators).Fresh comonomer feed may additionally be introduced to thepolymerisation reactor to control the ratio. It may be desirable topreferentially purge certain (co)monomer(s) that are formed in thetrimerisation reaction by, for example, heating or cooling a vapour (orliquid) slip (or recycle) stream within the polymerisation reaction (ordegassing) systems. This may for example be optimised by controllingcompressor knock-out or interstage conditions in recycle or degassingvent recovery compressors or by using dedicated condensing exchangers ordistillation apparatus.

[0086] The rate of addition of each component may be independentlycontrolled to allow variations in the ratio of components and thedensity of the polymer produced. Pressure, temperature, hydrogenaddition, halogenated hydrocarbon addition, electron donor addition,activator/retarder addition and other suitable variables may also bevaried to control the activity of each component and also allow controlof the polymer produced.

[0087] Once the polymer product is discharged from the reactor, anyassociated and absorbed hydrocarbons are substantially removed, ordegassed, from the polymer by, for example, pressure let-down or gaspurging using fresh or recycled steam, nitrogen or light hydrocarbons(such as ethylene). Recovered gaseous or liquid hydrocarbons may berecycled to a purification system or the polymerisation zone.

[0088] In the slurry phase polymerisation process the polymerisationdiluent is compatible with the polymer(s) and catalysts, and may be analkane such as hexane, heptane, isobutane, or a mixture of hydrocarbonsor paraffins. The polymerization zone can be, for example, an autoclaveor similar reaction vessel, or a continuous liquid full loop reactor,e.g. of the type well-known in the manufacture of polyethylene by thePhillips Process. When the polymerisation process of the presentinvention is carried out under slurry conditions the polymerisation ispreferably carried out at a temperature above 0° C., most preferablyabove 15° C. Under slurry conditions the polymerisation temperature ispreferably maintained below the temperature at which the polymercommences to soften or sinter in the presence of the polymerisationdiluent. If the temperature is allowed to go above the lattertemperature, fouling of the reactor can occur. Adjustment of thepolymerisation within these defined temperature ranges can provide auseful means of controlling the average molecular weight of the producedpolymer. A further useful means of controlling the molecular weight isto conduct the polymerization in the presence of hydrogen gas which actsas chain transfer agent. Generally, the higher the concentration ofhydrogen employed, the lower the average molecular weight of theproduced polymer.

[0089] In bulk polymerisation processes, liquid monomer such aspropylene is used as the polymerisation medium.

[0090] Methods for operating gas phase polymerisation processes are wellknown in the art. Such methods generally involve agitating (e.g. bystirring, vibrating or fluidising) a bed of catalyst, or a bed of thetarget polymer (i.e. polymer having the same or similar physicalproperties to that which it is desired to make in the polymerisationprocess) containing a catalyst, and feeding thereto a stream of monomer(under conditions such that at least part of the monomer polymerises incontact with the catalyst in the bed. The bed is generally cooled by theaddition of cool gas (e.g. recycled gaseous monomer) and/or volatileliquid (e.g. a volatile inert hydrocarbon, or gaseous monomer which hasbeen condensed to form a liquid). The polymer produced in, and isolatedfrom, gas phase processes forms directly a solid in the polymerisationzone and is free from, or substantially free from liquid. As is wellknown to those skilled in the art, if any liquid is allowed to enter thepolymerisation zone of a gas phase polymerisation process the quantityof liquid in the polymerisation zone is small in relation to thequantity of polymer present. This is in contrast to “solution phase”processes wherein the polymer is formed dissolved in a solvent, and“slurry phase” processes wherein the polymer forms as a suspension in aliquid diluent.

[0091] The gas phase process can be operated under batch, semi-batch, orso-called “continuous” conditions. It is preferred to operate underconditions such that monomer is continuously recycled to an agitatedpolymerisation zone containing polymerisation catalyst, make-up monomerbeing provided to replace polymerised monomer, and continuously orintermittently withdrawing produced polymer from the polymerisation zoneat a rate comparable to the rate of formation of the polymer, freshcatalyst being added to the polymerisation zone to replace the catalystwithdrawn from the polymerisation zone with the produced polymer.

[0092] Methods for operating gas phase fluidized bed processes formaking polyethylene, ethylene copolymers and polypropylene are wellknown in the art. The process can be operated, for example, in avertical cylindrical reactor equipped with a perforated distributionplate to support the bed and to distribute the incoming fluidising gasstream through the bed. The fluidising gas circulating through the bedserves to remove the heat of polymerisation from the bed and to supplymonomer for polymerization in the bed. Thus the fluidising gas generallycomprises the monomer(s) normally together with some inert gas (e.g.nitrogen or inert hydrocarbons such as methane, ethane, propane, butane,pentane or hexane) and optionally with hydrogen as molecular weightmodifier. The hot fluidising gas emerging from the top of the bed is ledoptionally through a velocity reduction zone (this can be a cylindricalportion of the reactor having a wider diameter) and, if desired, acyclone and or filters to disentrain fine solid particles from the gasstream. The hot gas is then led to a heat exchanger to remove at leastpart of the heat of polymerisation. Catalysts are preferably fedcontinuously or at regular intervals to the bed. At start up of theprocess, the bed comprises fluidisable polymer which is preferablysimilar to the target polymer. Polymer is produced continuously withinthe bed by the polymerization of the monomer(s). Preferably means areprovided to discharge polymer from the bed continuously or at regularintervals to maintain the fluidized bed at the desired height. Theprocess is generally operated at relatively low pressure, for example,at 10 to 50 bars, and at temperatures for example, between 50 and 135°C. The temperature of the bed is maintained below the sinteringtemperature of the fluidized polymer to avoid problems of agglomeration.

[0093] In the gas phase fluidized bed process for polymerisation ofolefins the heat evolved by the exothermic polymerisation reaction isnormally removed from the polymerisation zone (i.e. the fluidised bed)by means of the fluidising gas stream as described above. The hotreactor gas emerging from the top of the bed is led through one or moreheat exchangers wherein the gas is cooled. The cooled reactor gas,together with any make-up gas, is then recycled to the base of the bed.In the gas phase fluidised bed polymerisation process of the presentinvention it is desirable to provide additional cooling of the bed (andthereby improve the space time yield of the process) by feeding avolatile liquid to the bed under conditions such that the liquidevaporates in the bed thereby absorbing additional heat ofpolymerisation from the bed by the “latent heat of evaporation” effect.When the hot recycle gas from the bed enters the heat exchanger, thevolatile liquid can condense out. In one embodiment of the presentinvention the volatile liquid is separated from the recycle gas andreintroduced separately into the bed. Thus, for example, the volatileliquid can be separated and sprayed into the bed. In another embodimentof the present invention the volatile liquid is recycled to the bed withthe recycle gas. Thus the volatile liquid can be condensed from thefluidising gas stream emerging from the reactor and can be recycled tothe bed with recycle gas, or can be separated from the recycle gas andthen returned to the bed.

[0094] The method of condensing liquid in the recycle gas stream andreturning the mixture of gas and entrained liquid to the bed isdescribed in EP-A-0089691 and EP-A-0241947. It is preferred toreintroduce the condensed liquid into the bed separate from the recyclegas using the process described in our U.S. Pat. No. 5,541,270.

[0095] A number of process options can be envisaged when using thecatalysts of the present invention in an integrated process to preparehigher polymers i.e when component (d) is present. These options include“in series” processes in which the trimerisation and subsequentpolymerisation are carried in separate but linked reactors and “in situ”processes in which a both reaction steps are carried out in the samereactor.

[0096] In the case of a gas phase “in situ” polymerisation process,component (d) can, for example, be introduced into the polymerisationreaction zone in liquid form, for example, as a solution in asubstantially inert liquid diluent. Components (a), (b), (c) and (d) maybe independently added to any part of the polymerisation reactorsimultaneously or sequentially together or separately. Under thesecircumstances it is preferred the liquid containing the component(s) issprayed as fine droplets into the polymerisation zone. The dropletdiameter is preferably within the range 1 to 1000 microns. EP-A-0593083discloses a process for introducing a polymerisation catalyst into a gasphase polymerization. The methods disclosed in EP-A-0593083 can besuitably employed in the polymerisation process of the present inventionif desired.

[0097] Although not usually required, upon completion of polymerisationor copolymerisation, or when it is desired to terminate polymerisationor copolymerisation or at least temporarily deactivate the catalyst orcatalyst component of this invention, the catalyst can be contacted withwater, alcohols, acetone, or other suitable catalyst deactivators amanner known to persons of skill in the art.

[0098] The trimerisation catalyst is preferably (but optionally) addedbefore the polymerization catalyst such that the desired primary monomerto comonomer(s) ratio is established prior to introduction of thepolymerization catalyst. The desired comonomer composition at start-upmay however be achieved through introduction of fresh comonomer feed orthrough judicious initiation of the trimerisation reaction before orduring polymerization catalyst introduction.

[0099] In the presence of component (d) the polymerisation process ofthe present invention provides polymers and copolymers, especiallyethylene polymers, at high productivity (based on the amount of polymeror copolymer produced per unit weight of complex employed in thecatalyst system). This means that relatively very small quantities oftransition metal complexes are consumed in commercial processes usingthe process of the present invention. It also means that when thepolymerisation process of the present invention can be operated underpolymer recovery conditions that do not employ a catalyst separationstep, thus leaving the catalyst, or residues thereof, in the polymer(e.g. as occurs in most commercial slurry and gas phase polymerizationprocesses), the amount of transition metal complex in the producedpolymer can be very small.

[0100] By varying the ratio of components (a) (b), optionally (c) and(d) and/or by adding additional comonomers, catalysts of the presentinvention can provide a wide variety of branched polymers differing indensity and in other important physical properties.

[0101] A range of polyethylene polymers are considered accessibleincluding high density polyethylene, medium density polyethylene, lowdensity polyethylene, ultra low density polyethylene and elastomericmaterials. Particularly important are the polymers having a density inthe range of 0.91 to 0.93, generally referred to in the art as linearlow density polyethylene. Such polymers and copolymers are usedextensively in the manufacture of flexible blown or cast film.

[0102] Poly(1-hexene), poly(1-octene) and the like are also consideredaccessible, as are copolymers of e.g. 1-hexene and propylene, 1-hexeneand 1-octene and terpolymers of e.g. ethylene, 1-hexene and vinylacetate.

[0103] Dienes could also be incorporated into the polymeric products toenable cross-linking for e.g. elastomer and wire and cable applicationsDepending upon the use of the polymer product, minor amounts ofadditives are typically incorporated into the polymer formulation suchas acid scavengers, antioxidants, stabilizers, and the like. Generally,these additives are incorporated at levels of about 25 to 2000 ppm,typically from about 50 to about 1000 ppm, and more typically 400 to1000 ppm, based on the polymer.

[0104] In use, polymers or copolymers made according to the invention inthe form of a powder are conventionally compounded into pellets.Examples of uses for polymer compositions made according to theinvention include use to form fibres, extruded films, tapes, spunbondedwebs, moulded or thermoformed products, and the like. The polymers maybe blown or cast into films, or may be used for making a variety ofmoulded or extruded articles such as pipes, and containers such asbottles or drums. Specific additive packages for each application may beselected as known in the art. Examples of supplemental additives includeslip agents, anti-blocks, anti-stats, mould release agents, primary andsecondary anti-oxidants, clarifiers, nucleants, uv stabilizers, and thelike. Classes of additives are well known in the art and includephosphite antioxidants, hydroxylamine (such as N,N-dialkylhydroxylamine) and amine oxide (such as dialkyl methyl amine oxide)antioxidants, hindered amine light (uv) stabilizers, phenolicstabilizers, benzofuranone stabilizers, and the like. Various olefinpolymer additives are described in U.S. Pat. Nos. 4,318,845, 4,325,863,4,590,231, 4,668,721, 4,876,300, 5,175,312, 5,276,076, 5,326,802,5,344,860, 5,596,033, and 5,625,090.

[0105] Fillers such as silica, glass fibers, talc, and the like,nucleating agents, and colourants also may be added to the polymercompositions as known by the art.

[0106] The present invention is illustrated in the following Examples.

EXAMPLES

[0107] All manipulations were performed under anaerobic conditions.Solvents and gases were dried and degassed by standard procedures.Chemicals were purchased from the Aldrich Chemical Company unless statedotherwise. Methyl alumoxane (MAO) and modified methyl alumoxane (MMAO)were purchased from Witco as 10% w/w solutions in toluene or heptanesrespectively. (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ wassynthesized by literature procedures (See example 12 of WO97/37765).Cr(p-tolyl)Cl₂(THF)₃ was synthesized by literature procedure (Daly, J.J.; Seeden, R. P. A.; J. Chem. Soc. A, 1967, 736). Reaction productswere analysed by GCMS using 50 m×0.3 mm id, CP sil. CBS-MS, df=0.4 μmcolumns, an initial temperature of −30° C., hold 1 min, ramp rate 7°C./min, final temperature 280° C. and final hold of 5 mins. Molarquantities of catalyst are based upon the molar quantity of chromiumsource used in their preparation.

Example 1

[0108] A Schlenk tube was charged with CrCl₃(THF)₃ (8 mg, 0.02 mmol) and(2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ (10 mg, 0.02 mmol), 10 mlTHF was added and the solution stirred for 2 hours. After this time,solvent was removed under reduced pressure and the resultant solidsuspended in 50 ml toluene. MAO (4.2 ml, 6.0 mmol, 300 equivalents) wasadded and an immediately a green solution was observed. The solutionplaced under an ethylene atmosphere (1 bar). An immediate exotherm wasobserved. The reaction was run for 60 minutes during which time thevessel was left open to a supply of ethylene at 1 bar. The catalyst wasthen destroyed by addition of 50 ml dilute aqueous HCl, the organiclayer separated and dried over MgSO₄. The product mass, recorded byweighing the mass gain of the Schlenk reaction vessel, was 10.3 g. GCMSanalysis of the reaction products gave the following productdistribution: wt % Total Product Butenes 0.04 1-Hexene 82.17 2-Hexene0.44 3-Hexene 0.15 1-Octene 1.37 Decenes 14.39 C12 olefins 0.20 C14olefins 0.78 C16 olefins 0.00 C18 olefins 0.00

Example 2

[0109] The procedure of Example 1 was followed, with the exception that300 equivalents of MMAO (4.2 ml, 6.0 mmol) was used in place of MAO. Theproduct mass was 8.8 g.

Example 3

[0110] The procedure of Example 1 was followed, with the exception that100 equivalents of (iBu₂AlO)₂ (2.0M solution in toluene, 1.0 ml, 2.0mmol) was used in place of MAO. The product mass was 1.3 g.

Example 4

[0111] The procedure as Example 1 was followed with the exception thatCrCl₂ (3 mg, 0.02 mmol) was used in place of CrCl₃(THF)₃. The productmass was 5.6 g.

Example 5

[0112] A Schlenk vessel was charged with Cr(p-tolyl)Cl₂(THF)₃ (9 mg,0.02 mmol) and (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ (10 mg, 0.02mmol), 50 ml toluene was added, and the solution stirred for 5 minutes.MMAO (4.2 ml, 6.0 mmol) 300 equivalents) was added and the solutionplaced under an ethylene atmosphere (1 bar). The reaction was run for 60minutes during which time the vessel was left open to a supply ofethylene at 1 bar. The reaction was worked-up as described in example 1.The product mass was 11.0 g.

Example 6

[0113] The procedure as Example 1 was followed with the exception that0.04 mmol (20 mg) of (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ wasused rather than 0.02 mmol. The product mass was 9.5 g.

Example 7

[0114] The procedure as Example 2 was followed with the exception that0.01 mmol (5 mg) of (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ was usedrather than 0.02 mmol. The product mass was 3.3 g.

Example 8

[0115] A Schlenk tube was charged with(2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ (415 mg, 0.8 mmol) andCrCl₃(THF)₃ (300 mg, 0.8 mmol) and 30 ml dichloromethane added. A brightblue solution formed almost immediately which was stirred for 2 hours.After this time solvent was removed under reduced pressure to yield ablue solid; this was washed with diethyl ether and dried in vacuo. Afurther Schlenk tube was charged with mg of this compound and 50 mltoluene added. MMAO (16.8 ml, 24 mmol, 300 equivalents) was added andthe solution placed under an ethylene atmosphere (1 bar). The reactionwas run for 60 minutes during which time the vessel was left open to asupply of ethylene at 1 bar. The reaction was worked-up as described inexample 1. The product mass was 2.5 g.

Example 9

[0116] Preparation of MAO on Silica

[0117] Toluene (200 ml) was added to a vessel containing silica(prepared according to procedures described in WO 99/12981 example 37.1.Silica was supplied by Crosfield as grade ES70X), calcined at 200° C.overnight, 20.5 g after calcination) under an inert atmosphere. Theslurry was mechanically stirred and MAO (1.5 M, 62.1 mmol, 41.4 ml) wasadded via syringe. The mixture was stirred for 1 hour at 80° C. beforeremoving excess toluene and drying under vacuum to obtain 15% w/w MAO onsilica in quantitative yield.

[0118] Trimerisation Using a Supported Catalyst Composition

[0119] A Schlenk vessel was charged with CrCl₃(THF)₃ (8 mg, 0.02 mmol)and (2-methoxyphenyl)2PN(Me)P(2-methoxyphenyl)₂ (10 mg, 0.02 mmol), 10ml THF was added and the solution stirred for 2 hours. After this time,solvent was removed under reduced pressure and the resultant solidsuspended in 20 ml toluene. MAO (1.4 ml, 2 mmol, 100 equivalents) wasadded and an immediately a green solution was observed. This solutionwas then transferred via cannula to a Schlenk tube containing a slurryof 15% w/w MAO on silica (prepared as described above) in toluene (1 gof MAO/Silica in 30 ml toluene). The green colour of the solution wasquickly transferred onto the silica/MAO and a colourless supernatantremained. This slurry was stirred and placed under an ethyleneatmosphere (1 bar). The reaction was run for 60 minutes during whichtime the vessel was left open to a supply of ethylene at 1 bar. Thereaction was worked-up as described in example 1. The product mass was8.9 g. wt % Total Product 1-Hexene 62 Octenes 0.28 Decenes 30.3

Example 10

[0120] A Schlenk vessel was charged with CrCl₃(THF)₃ (8 mg, 0.02 mmol)and (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂ (10 mg, 0.02 mmol), 10ml THF was added and the solution stirred for 2 hours. After this time,solvent was removed under reduced pressure, the resultant solidsuspended in 10 ml toluene and MAO (4.2 ml, 6.0 mmol, 300 equivalents)added. This solution was then injected into an autoclave at 8 barethylene pressure and 50° C. The diluent was isobutane. The reaction wasrun for 1 hour at 8 bar ethylene pressure and 50° C. after which timeethylene and isobutane gases were vented. The reaction products werethen worked up as described in Example 1. The mass of product recoveredwas 40.0 g and the productivity over one hour was 2000 g/mmol.h. GCMSanalysis gave the following product distribution: wt % Total ProductButene 0.00 1-Hexene 88.37 2-Hexene 0.12 3-Hexene 0.00 Octenes 3.95Decenes 6.61 C12 olefins 0.33 C14 olefins 0.20 C16 olefins 0.00 C18olefins 0.00

Example 11

[0121] The procedure of Example 10 was followed with the followingexceptions: 500 ml toluene diluent was used in place of isobutene and0.01 mmol of catalyst was used. The reactor conditions were maintainedat 50° C. and 8 bar ethylene pressure over the 60 minute run time. Astable gas uptake profile over the run time was observed. The mass ofproduct recovered was 72.7 g and the productivity over one hour was 7270g/mmol.h (134 700 g/gCr.h.) wt % Total Product 1-Hexene 86 Octenes 1.8Decenes 8.7

Example 12

[0122] The procedure of Example 11 was followed with the exceptions thatthe reactor conditions were maintained at 80° C. and 20 bar ethylenepressure over the 60 minute run time. 0.0025 mmol of catalyst was used.The mass of product recovered was 141 g and the productivity over onehour was 56400 g/mmol.h (1 033 200 g/gCr.h.) wt % Total Product 1-Hexene88.8 Octenes 1.8 Decenes 7.4

Example 13

[0123] The procedure of Example 11 was followed with the exceptions thatthe reactor conditions were maintained at 108° C. and 8 bar ethylenepressure over the 60 minute run time. 0.01 mmol of catalyst was used.The mass of product recovered was 51.6 g and the productivity over onehour was 5160 g/mmol.h (95 900 g/gCr.h) wt % Total Product 1-Hexene 86.6Decenes 11

Example 14

[0124] The procedure of Example 11 was followed with the exceptions that1 bar of hydrogen was added to the reactor before the run. 0.01 mmol ofcatalyst was used. The mass of product recovered was 94.7 g and theproductivity over one hour was 9470 g/mmol.h (175 300 g/gCr.h.) wt %Total Product 1-Hexene 82 Octenes 0.45 Decenes 13.2

Example 15

[0125] The procedure of Example 11 was followed with the exception that0.01 mmol of a supported catalyst, prepared as described in Example 8,was used. The mass of product recovered was 49.8 g and the productivityover one hour was 4980 g/mmol.h (90 406 g/gCr.h.) wt % Total Product1-Hexene 89 Octenes 0.58 Decenes 7.9

Example 16

[0126] The procedure of Example 11 was followed with the exceptions that100 ml of 1-butene was added to the reactor before the run and 400 ml oftoluene diluent was used. The reactor conditions were maintained at 80°C. and 4 bar ethylene pressure. 0.02 mmol of catalyst was used. The massof product recovered was 49.4 g and the productivity over one hour was2470 g/mmol.h (46125 g/gCr.h.) wt % Total Product 1-Hexene 60 Octenes 25Decenes 10.9

Example 17

[0127] The procedure of Example 1 was followed with the exceptions thatthe run time in this case was 90 minutes and the product mass wasrecorded by weighing the mass gain of the Schlenk reaction vessel atvarious times through the run. Time (mins) 15 30 45 60 90 Mass gain (g)2.7 5.2 7.6 10.0 13.0

[0128] GCMS analysis of the product after 90 minutes gave the followingproduct distribution: wt % Total Product Butenes 0.00 1-Hexene 64.102-Hexene 0.13 3-Hexene 0.00 Octenes 0.44 Decenes 28.93 C12 olefins 0.13C14 olefins 4.99 C16 olefins 0.00 C18 olefins 0.59

Example 18

[0129] The procedure of Example 2 was followed with the exceptions that20 ml of toluene was used and 20 ml of 1-dodecene was added at the startof the run. The product mass was 2.1 g. wt % Total Product 1-Hexene 37Decene 27 C16 olefins 29

Example 19

[0130] The procedure of Example 2 was followed with the exceptions that20 ml of toluene was used and 20 ml of 1-tetradecene was added at thestart of the run. The product mass was 3.2 g. wt % Total Product1-Hexene 35.3 Decene 6.7 C18 olefins 50.8

Example 20

[0131] The procedure of Example 9 was followed with the exceptions that20 ml of toluene was used and 20 ml of 1-dodecene was added at the startof the run, in this case the run was for 4.5 hours. The product mass was7.5 g. wt. % Total Product 1-Hexene 38 Decene 24 C16 olefins 38

Example A (Comparative)

[0132] The procedure of Example 1 was followed with the exceptions that1,2-bis(diphenylphosphino)ethane (8 mg, 0.02 mmol) was used in place of(2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂. No product was formed.

Example 21

[0133] The procedure of Example 1 was followed, with the exception thattris(2-methoxymethoxyphenyl)phosphane (18 mg, 0.04 mmol) was used inplace of (2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂. The product masswas 1.2 g.

[0134] GCMS analysis of the reaction products gave the following productdistribution: wt % Total Product 1-Hexene 90.66 2-Hexene 2.94 1-Octene2.85 Decenes 3.54

Example B (Comparative)

[0135] The procedure of Example 20 was followed with the exception thattriphenylphosphane (11 mg, 0.04 mmol) was used in place oftris(2-methoxymethoxyphenyl)phosphane. No product was formed

Example 22

[0136] (Co)Polymerisation of Ethylene

[0137] An autoclave was charged with isobutane (500 ml) andtriethylaluminium (2.0M solution in toluene, 1.5 ml, 3 mmol). Theautoclave was pressurized to 8 bar ethylene pressure and heated to 50°C.

[0138] A catalyst (0.02 mmol), prepared as described in Example 8, wasthen injected as a slurry in 10 ml toluene. Almost immediately, a slurryof Ziegler catalyst (0.05 g), prepared according to U.S. Pat. No.5,470,812, example A, was injected as a slurry in 10 ml toluene. Thereaction was run for 1 hour at 8 bar ethylene pressure and 50° C. afterwhich time ethylene and isobutane gases were vented. The resultantpolymer was washed with dilute aqueous HCl and then methanol and driedin vacuo. The mass of polymer recovered was 36.0 g. NMR spectroscopy ofthe polymer shows the presence of butyl branches, indicating that anethylene/1-hexene copolymer was produced.

Example 23

[0139] (Co)Polymerisation of Ethylene

[0140] A supported catalyst (0.01 mmol) was prepared as described inExample 9 in 40 ml toluene. In a separate Schlenk tube, [rac-(ethylenebridged bis indenyl) zirconium dichloride] (mg, 0.01 mmol) was disolvedin 10 ml toluene and MMAO (7 ml, 10.0 mmol, 1000 equivalents) added.This second solution was added via canula to the supported catalystslurry and the resultant slurry stirred under an ethylene atmosphere at1 bar. The reaction was ran for 60 minutes during which time the vesselwas left open to a supply of ethylene at 1 bar. The catalysts were thendestroyed by careful addition of 50 ml dilute aqueous HCl. Both organicand aqueous fractions were then added to 500 ml of acetone, causingprecipitation of the polymer produced. The polymer was washed withfurther portions of acetone and dried in vacuo. The mass of polymerrecovered was 3.4 g. NMR spectroscopy of the polymer shows the presenceof butyl branches, indicating that an ethylene/1-hexene copolymer wasproduced.

1. Catalyst comprising (a) a source of chromium, molybdenum or tungsten;(b) a ligand containing at least one phosphorus, arsenic or antimonyatom bound to at least one hydrocarbyl or beterohydrocarbyl group havinga polar substituent, but excluding the case where all such polarsubstituents are phosphane, arsane or stibane groups; and optionally (c)an activator.
 2. Catalyst according to claim 1, wherein the catalyst issupported.
 3. Supported catalyst having a productivity per mole ofcatalyst of at least 50%, preferably at least 70% of its productivitywhen unsupported, which catalyst preferably comprises (a) a source of aGroup 3 to 10 transition metal; (b) a ligand containing at least onephosphorus, arsenic or antimony atom bound to at least one hydrocarbylor heterohydrocarbyl group having a polar substituent, but excluding thecase where all such polar substituents are phosphane, arsane or stibanegroups; and optionally (c) an activator.
 4. Catalyst according to claim3, wherein the productivity is for trimerisation of olefins.
 5. Catalystaccording to claim 3 or 4, wherein the support is selected from silica,alumina, MgCl₂, zirconia, polyethylene, polypropylene, polystyrene, orpoly(aminostyrene).
 6. Catalyst according to claim 3, 4 or 5, whereincomponent (a) is a source of chromium, molybdenum or tungsten. 7.Catalyst according to any preceding claim, wherein component (a) is asource of chromium.
 8. Catalyst according to any preceding claim,wherein the ligand of component (b) has the formula(R¹)(R²)X-Y-X(R³)(R⁴) or X(R¹)(R²)(R³), wherein X is phosphorus, arsenicor antimony; Y is a linking group; and R¹, R², R³ and R⁴ are eachindependently hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl orsubstituted heterohydrocarbyl groups, at least one of which in eachformula has a polar substituent which is not a phosphane, arsane orstibane group, and any of the groups R¹-R⁴ may independently be linkedto one or more of each other or to the bridging group Y, to form acyclic structure together with X or X and Y.
 9. Catalyst according toany preceding claim, wherein X is phosphorus.
 10. Catalyst according toclaim 8 or 9, wherein the optionally substituted hydrocarbyl orheterohydrocarbyl groups of R¹, R², R³ and R⁴ are independently selectedfrom methyl, ethyl, ethylenyl, propyl, butyl, cyclohexyl, benzyl,phenyl, tolyl, xylyl, mesityl, biphenyl, naphthyl, anthracenyl, methoxy,ethoxy, phenoxy (i.e. —OC₆H₅), tolyloxy (i.e. —OC₆H₄(CH₃)), xylyloxy,mesityloxy, dimethylamino, diethylamino, methylethylamino, thiomethyl,thiophenyl, trimethylsilyl or dimethylhydrazyl.
 11. Catalyst accordingto any of claims 8 to 10, wherein those of R¹ to R⁴ having polarsubstituents are each independently substituted phenyl, substitutednaphthyl or substituted anthracenyl groups.
 12. Catalyst according toclaim 11, wherein the polar substituents are independently selected frommethoxy, ethoxy, isopropoxy, C₃-C₂₀ alkoxy, phenoxy, pentafluorophenoxy,trimethylsiloxy, dimethylamino, methylsulphanyl, tosyl, methoxymethyl,methylthiomethyl, 1,3-oxazolyl, methoxymethoxy, hydroxyl, amino,sulphate, nitro, phosphane, arsane and stibane.
 13. Catalyst accordingto claim 12, wherein those of R¹ to R⁴ having polar substituents areeach independently o-methoxy phenyl or o-methoxymethoxy phenyl. 14.Catalyst according to any one of claims 8 to 13, wherein all of R¹ to R⁴independently have a polar substituent which is not a phosphane, arsaneor stibane group.
 15. Catalyst according to any one of claims 8 to 14,wherein Y is a hydrocarbyl, substituted hydrocarbyl, heterohydrocarbyl,substituted hydrocarbyl or substituted heterohydrocarbyl bridging group,or an inorganic bridging group.
 16. Catalyst according to claim 15,wherein the Y is methylene, 1,2-ethane, 1,2-phenylene, 1,3-propane,1,2-catechol, 1,2-dimethylhydrazine, or —N(R⁵)— where R⁵ is hydrogen,hydrocarbyl or substituted hydrocarbyl.
 17. Catalyst according to claim16, wherein Y is —N(R⁵)—, and R⁵ is hydrogen, C₁-C₆ alkyl or phenyl. 18.Catalyst according to any preceding claim, wherein component (b) isselected from the following: (2-methoxyphenyl)(phenyl)PN(Me)P(phenyl)₂(2-methoxyphenyl)₂PN(Me)P(phenyl)₂(2-methoxyphenyl)(phenyl)PN(Me)P(2-methoxyphenyl)(phenyl)(2-methoxyphenyl)₂PN(Me)P(2-methoxyphenyl)₂(2-ethoxyphenyl)2PN(Me)P(2-ethoxyphenyl)₂(2-isopropoxyphenyl)₂PN(Me)P(2-isopropoxyphenyl)₂(2-hydroxyphenyl)₂PN(Me)P(2-hydroxyphenyl)₂(2-nitrophenyl)₂PN(Me)P(2-nitrophenyl)₂(2,3-dimethoxyphenyl)₂PN(Me)P(2,3-dimethoxyphenyl)₂(2,4-dimethoxyphenyl)₂PN(Me)P(2,4-dimethoxyphenyl)₂(2,6-dimethoxyphenyl)₂PN(Me)P(2,6-dimethoxyphenyl)₂(2,4,6-trimethoxyphenyl)2PN(Me)P(2,4,6-trimethoxyphenyl)₂(2-dimethoxyphenyl)(2-methylphenyl)PN(Me)P(2-methylphenyl)2[2-(dimethylamino)phenyl]₂PN(Me)P[2-(dimethylamino)phenyl]₂(2-methoxymethoxyphenyl)₂PN(Me)P(2-methoxymethoxyphenyl)₂(2-methoxyphenyl)₂PN(Ethyl)P(2-methoxyphenyl)₂(2-methoxyphenyl)₂PN(Phenyl)P(2-methoxyphenyl)₂(2-methoxyphenyl)₂PN(Me)N(Me)P(2-methoxyphenyl)2(2-methoxyphenyl)₂PCH₂P(2-methoxyphenyl)₂(2-methoxyphenyl)₂PCH₂CH₂P(2-methoxyphenyl)₂tri(2-methoxymethoxyphenyl)phosphane i.e.

tri(2-methoxyphenyl) phosphane.
 19. Catalyst according to any precedingclaim, wherein component (c) is selected from trimethylaluminium (TMA),triethylaluminium (TEA), tri-isobutylaluminium (TIBA),tri-n-octylaluminium, methylaluminium dichloride, ethylaluminiumdichloride, dimethylaluminium chloride, diethylaluminium chloride,ethylaluminiumsesquichloride, methylaluminiumsesquichloride, alumoxanes,tetrafluoroboric acid etherate, silver tetrafluoroborate, sodiumhexafluoroantimonate, boroxines, NaBH₄, trimethylboron, triethylboron,dimethylphenylammoniumtetra(phenyl)borate, trityltetra(phenyl)borate,triphenylboron, dimethylphenylammonium tetra(pentafluorophenyl)borate,sodium tetrakis[(bis-3,5-trifluoromethyl)phenyl]borate,H⁺(OEt₂)₂[(bis-3,5-trifluoromethyl)phenyl]borate,trityltetra(pentafluorophenyl)borate and tris(pentafluorophenyl) boron,or mixtures thereof.
 20. Catalyst for the trimerisation andpolymerisation of 1-olefins, further comprising one or more catalysts(d) suitable for the polymerisation, oligomerisation or other chemicaltransformation of olefins.
 21. Catalyst according to claim 20, whereincatalyst (d) is selected from Ziegler-Natta catalysts, metallocenecatalysts, monocyclopentadienyl or “constrained geometry” catalysts,beat activated supported chromium oxide catalysts, late transition metalcatalysts, and single site polymerisation catalysts.
 22. Catalystaccording to any preceding claim, which has a trimerisation productivityof at least 15000 g product per mmol catalyst per hour, preferably atleast 30000 g product per mmol catalyst per hour, at a temperature of110° C. or less and an ethylene partial pressure of 21 bar or less. 23.Catalyst for the trimerisation of olefins, wherein the catalystproductivity decays at a rate of less than 10% per hour.
 24. Catalystfor the trimerisation of ethylene, which has a trimerisationproductivity of at least 15000 g product per mmol catalyst per hour,preferably at least 30000 g product per mmol catalyst per hour, at atemperature of 110° C. or less and an ethylene partial pressure of 21bar or less.
 25. Catalyst according to any of claims 22 to 24 which issupported, preferably on a support selected from silica, alumina, MgCl₂,zirconia, polyethylene, polypropylene, polystyrene, orpoly(aminostyrene).
 26. Process for the trimerisation of olefins,comprising contacting a monomeric olefin or mixture of olefins undertrimerisation conditions with a catalyst which comprises (a) a source ofa Group 3 to 10 transition metal; (b) a ligand containing at least onephosphorus, arsenic or antimony atom bound to at least one hydrocarbylor heterohydrocarbyl group having a polar substituent, but excluding thecase where all such polar substituents are phosphane, arsane or stibanegroups; and optionally (c) an activator.
 27. Process according to claim26, wherein the catalyst is as defined in any of claims 1 to
 25. 28.Process according to claim 26 or 27, wherein the olefin or mixture ofolefins is additionally contacted with a further catalyst (d) suitablefor the polymerisation, oligomerisation or other chemical transformationof olefins, such that the trimerisation products are incorporated into ahigher polymer or other chemical product.
 29. Process according to anyone of claims 26 to 28, wherein the monomeric olefin is ethylene. 30.Process according to any one of claims 26 to 28, wherein the mixture ofolefins comprises ethylene and one or more C3-C36 monoolefin. 31.Process according to claim 30, wherein the C3-C36 monoolefin is a C4-C20monoolefin.
 32. Process according to claim 31, wherein the C4-C20monoolefin comprises butene, hexene, decene, a C12 olefin or a C14olefin.
 33. Process according to any one of claims 26 to 32, wherein atleast 85 wt %, preferably at least 90 wt % of the trimerisation reactionproduct is one of the following: 1-hexene, 1-octene, 1-decene, a C12olefin, a C14 olefin, a C16 olefin or a C18 olefin.
 34. Processaccording to any one of claims 26 to 33, wherein the reactiontemperature is less than 100° C., and/or the reaction pressure is below30 bara.
 35. Process according to any one of claims 26 to 34, whereinthe residence time in the polymerisation reactor is less than 4 hours,preferably less than 3 hours.
 36. Process according to any one of claims26 to 35 wherein the reaction conditions are solution phase, slurryphase or gas phase.
 37. Process according to claim 36 wherein thereaction is conducted under gas phase fluidised bed conditions. 38.Process according to claim 28, wherein the trimerisation reactor isupstream or downstream of at least one polymerisation or oligomerisationreactor.
 39. Process according to claim 28, wherein the trimerisationreactor is incorporated into the reaction loop of at least onepolymerisation or oligomerisation reactor.
 40. Process according toclaim 39, wherein the trimerisation reactor is incorporated into aside-stream taken from said reaction loop.
 41. Process according toclaim 28, wherein the trimerisation reaction product is produced in orintroduced into at least one polymerisation or oligomerisation reactor.42. Process according to any one of claims 28 and 38 to 40, wherein atleast one trimerisation reaction product is separated from the remainderof the trimerisation reaction products prior to (re)introduction intothe polymerisation or oligomerisation reactor.
 43. Process according toany one of claims 26 to 42, wherein the trimerisation reaction isconducted in the presence of hydrogen and/or a halide source.
 44. Use ofa mixture of components (a), (b), optionally (c) and optionally (d), asdefined in any of claims 1 to 25, as a catalyst for the trimerisation ofolefins.
 45. Use of a mixture of components (a), (b), (d) and optionally(c), as defined in any of claims 1 to 25, as a catalyst for thehomopolymerisation of ethylene to produce polyethylene having a densityof 960 g/cm³ or less, preferably 940 g/cm³ or less and more preferably920 g/cm³ or less.